Coupling devices including hinge pins of the above type are used conventionally for flexibly interconnecting conveyor belt ends by means of connector elements which intermesh to form a connector channel into which the coupling rod, also referred to as a hinge pin, is inserted. The hinging of the connector elements to each other permits the movement of the conveyor belt even around a driving wheel. The coupling rods are exposed to high loads during operation. For increasing the wear and tear resistance the connector rods are conventionally made of steel cable strands which are armored by a steel helix.
U.S. Pat. 4,023,239 (Stolz) discloses a coupling rod of the just mentioned type in which a flexible core is enclosed by a plurality of sleeves, each of which has curved end faces in contact with mating end faces of adjacent sleeves. Such conventional coupling rods have excellent wear and tear resistance. However, there is room for improving these rods with a view to facilitating their insertion into the channel formed by the eyelets of the connector elements when these connector elements intermesh.